Tomas EM3207 build. Voltages Check

[Slowpoke101]

The 4013 should not freeze in filter/matrix mode.
Measure the voltage on IC4 pin 2 when filter/matrix is selected. It should vary with the range control.
Double check the wiring of the flanger / filter-matrix switch.

You are quite correct with your comment that 4049B chips can be hard to locate. Since you're in Perth, I thought to check both Altronics and Jaycar - Nope. Only the unbuffered version. I must be rather fortunate to have several of both types. I haven't bought any for years.

I quickly tested the alternate oscillator configuration and I got similar results to Dr Alx. I should have completed my build of this effect tomorrow. Once the build is completed I will be able to assist you more easily.Just finished drilling the PCB.

I built the oscillator/divider/LFO on a piece of perf' board so I could carry out some tests that may have helped sort your problem out. The more I looked at this little effects unit the more I wanted to build one. Sure, I've got other flangers but a correctly sounding Electric Mistress Clone was just too hard to resist.

[AS74]

I'll be glad to hear of your results Slowpoke.

[DrAlx]

Regarding the 4049B vs 4049UBE chips. 
I also found the 4049B hard to find. When I finally got some, I took measurements comparing 4049B vs 4049UBE vs 4050B.
Results are here: http://www.diystompboxes.com/smfforum/index.php?topic=117938.msg1096479#msg1096479.

(Note: If you are using Chrome, you can install a browser plugin to get around Photobucket stopping the image from displaying).

I found no measurable difference between the 4049UBE and 4049B.  I did see a slightly higher gain BBD gain when using the 4050B though.
The 4049 gives you get a small improvement in BBD gain of about 0.2 dB at the high clock rates compared to using a 4013 with no buffer.
It's a measurable difference, but you would have a hard time actually hearing any difference in a blind test.

Regarding setting the clock trimmer, remember that the info on the EM Mystery Page refers to the SAD1024 chip which requires a lower rate clock.  Using that rate on the EM3207 will mean the clock will be running at half the required rate (and so give more clock noise).
Use the procedure here: http://www.diystompboxes.com/smfforum/index.php?topic=91981.msg1047491#msg1047491
to set the clock rate instead.  No scope required.

[AS74]

Good info as always DrAlx.  I have read previously the link to the setting the clock.  I hear no delay sound as you demonstrated on sound cloud. 

I did make oscillator changes that you put forward in the other thread. 

[Slowpoke101]

OK..After finally getting my copy of this wonderful effect mostly together after work got in the way...A few measurements and observations that may help (or hinder).

You said that with your pedal when you select Filter Matrix mode the 4013 stops. This implies that the clock oscillator has stopped. This can happen if its control voltage on pin 2 of IC4 goes either too high or too low.

I measured the following voltages on IC3a. Bear in mind that the voltage output on IC3a (pin 1) is controlled by the setting of the range control. There should be no varying voltages as when in flange mode. The rate pot has no effect on IC3a pin 1 when in Filter Matrix mode.

Range Pot set to minimum;
IC3a Pin1 = 1.051V    Pin 2 = 1.051   Pin 3 = 1.051

Range Pot set to maximum;
IC3a Pin1 = 3.861V    Pin 2 = 1.061   Pin 3 = 1.061

In Flange mode (rate set to minimum);
Range Pot set to minimum;
IC3a Pin 1 = 1.113 to 2.03V (Pins 2 and 3 are nearly at the same voltages)

Range Pot set to maximum;
IC3a Pin 1 = 1.25 to 4.01V (Pins 2 and 3 are nearly at the same voltages as Pin 1)

Check your selector switch wiring if you don't get similar readings.

I have an annoying problem with my unit. Several faulty MN3207 ICs - (low output) No idea when or when I got them. So another order for after the Christmas break. I am modifying my unit to accept a MN3007 chip (which I have and it does work). However I did do some other tests with 4049B, 4049UB and 4050B chips and I totally agree with Dr Alx's own observations - No real differences at all. Waveform shape is still within the specifications for both MN3207 and MN3007.

I have not yet checked how well the alternative oscillator works with the rest of the effect yet. No point until I have the BBD working correctly. Should be done with that tomorrow.

[AS74]

Ok then.  All voltages on pins 1,2 and 3 of IC3 match yours except when in Flange mode - Max range.
Pin 1 is good, pins 2 and 3 are only getting approximately 1/2 of pin 1's max voltage at the top of the sweep.

I've checked switch wiring and swapped switches, just in case and all seems good there.

Thanks

Adam

[Slowpoke101]

I made an error in my previous post. Trying to take measurements whilst being interrupted every few minutes can lead to mistakes. Your measurements in flange mode agree with mine - correct measurements below.

In Flange mode (rate set to minimum);
Range Pot set to minimum;
IC3a Pin 1 = 1.113 to 2.03V  Pin 2 = 1.112 to 2.03V   Pin 3 = 1.112 to 2.03V

Range Pot set to maximum;
IC3a Pin 1 = 1.25 to 4.01V    Pin 2 = 1.112 to 2.03V   Pin 3 = 1.112 to 2.03V

I have got mine to work with the MN3007 chip and it does sound pretty good, just a bit of clock noise from the BBD. Helps to have some supply filtering. Have that sorted soon. Once it's all running satisfactorily I will try the oscillator mod' and see what I find.

[AS74]

Some more voltages from the 324 and 311 to compare will at least give me something to check.

Would you be so kind?

Cheers
Adam

[Slowpoke101]

Finally got back to the bench. Managed to carry out quite a few tests. 

Firstly, do not use the alternative oscillator configuration as it appears to introduce some noise onto the power rails. Additional filtering will be required to tame it. Damn good oscillator though. Very impressive range.
Go back to the original oscillator config with the following mods;

Leave R34 as 1K for the moment - this will be changed when you've got the oscillator running.
C17 change to 56pF
R33 change to 10K

Set RT3 for max resistance. Set the effect to flange mode with range fully CW and apply power. Make sure that it flanges.
Once you have got the effect flanging change R34 to 3K3 or 4K7 and make sure that the flange effect still works. Changing R34 changes the clocking noise that you may be hearing.

In the build notes there is a reference to six 100nF capacitors to be soldered across each IC's power to ground. I recommend that you do this. Extra decoupling at the ICs never goes astray.

Voltages on IC3 - Rate set Min (CCW), Range set Max (CW). Battery = 9.33V

Pin 1 = 1.25 to 4.02V                                      Pin 14 = 4.59V
Pin 2 = 1.10 to 2.01V                                      Pin 13 = 4.59V
Pin 3 = 1.10 to 2.01V                                      Pin 12 = 4.6V
Pin 4 = 9.18V (VCC)                                        Pin 11 = 0V (GND)
Pin 5 = 2.45 to 6.0V                                        Pin 10 = 4.21 to 4.31V
Pin 6 = 4.17 to 4.27V                                      Pin 9  = 4.21 to 4.31V
Pin 7 = 0.35 to 7.91V                                      Pin 8  = 3.05 to 5.5V

Note: Pins 12, 13 & 14 constitute the bias voltage adjustment by RT2. Your measurements will be different.

IC4: Standard oscillator configuration. Rate set to Min (CCW). Range set Max (CW).

Pin 1 = 0V                                      Pin 8 = 9.26V (VCC)
Pin 2 = 1.25 to 4.02V                       Pin 7 = 8.1 to 9.14V
Pin 3 = 1.05 to 2.65V                       Pin 6 = 9.26V
Pin 4 = 0V (GND)                             Pin 5 = 9.26V

I hope these voltages will help to make sense of your unit.

I did try out DrAlx's last modifications;

http://www.diystompboxes.com/smfforum/index.php?topic=91981.msg1088655#msg1088655

The mods sound excellent. Try them once you are satisfied that your unit is working correctly.

[AS74]

Awesome!  Might be a few days, what with Christmas and all that.
Thank you Sir.

[AS74]

Finally got to have a go at it.

IC Voltages look to coincide with yours, except IC4 pin 7 : 1.42V - 2.93V.  Yours getting up to VCC.
Maybe just where the trim is set on mine after fiddling with it.  I get no flanging with guitar plugged in right through RT3's range.

Almost time to scrap and start over.